124 lines
2.5 KiB
Go
124 lines
2.5 KiB
Go
|
package err113
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"go/ast"
|
||
|
|
"go/token"
|
||
|
|
"go/types"
|
||
|
|
|
||
|
|
"golang.org/x/tools/go/analysis"
|
||
|
|
)
|
||
|
|
|
||
|
|
func inspectComparision(pass *analysis.Pass, n ast.Node) bool { // nolint: unparam
|
||
|
|
// check whether the call expression matches time.Now().Sub()
|
||
|
|
be, ok := n.(*ast.BinaryExpr)
|
||
|
|
if !ok {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
// check if it is a comparison operation
|
||
|
|
if be.Op != token.EQL && be.Op != token.NEQ {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
if !areBothErrors(be.X, be.Y, pass.TypesInfo) {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
oldExpr := render(pass.Fset, be)
|
||
|
|
|
||
|
|
negate := ""
|
||
|
|
if be.Op == token.NEQ {
|
||
|
|
negate = "!"
|
||
|
|
}
|
||
|
|
|
||
|
|
newExpr := fmt.Sprintf("%s%s.Is(%s, %s)", negate, "errors", rawString(be.X), rawString(be.Y))
|
||
|
|
|
||
|
|
pass.Report(
|
||
|
|
analysis.Diagnostic{
|
||
|
|
Pos: be.Pos(),
|
||
|
|
Message: fmt.Sprintf("do not compare errors directly %q, use %q instead", oldExpr, newExpr),
|
||
|
|
SuggestedFixes: []analysis.SuggestedFix{
|
||
|
|
{
|
||
|
|
Message: fmt.Sprintf("should replace %q with %q", oldExpr, newExpr),
|
||
|
|
TextEdits: []analysis.TextEdit{
|
||
|
|
{
|
||
|
|
Pos: be.Pos(),
|
||
|
|
End: be.End(),
|
||
|
|
NewText: []byte(newExpr),
|
||
|
|
},
|
||
|
|
},
|
||
|
|
},
|
||
|
|
},
|
||
|
|
},
|
||
|
|
)
|
||
|
|
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
func isError(v ast.Expr, info *types.Info) bool {
|
||
|
|
if intf, ok := info.TypeOf(v).Underlying().(*types.Interface); ok {
|
||
|
|
return intf.NumMethods() == 1 && intf.Method(0).FullName() == "(error).Error"
|
||
|
|
}
|
||
|
|
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
func isEOF(ex ast.Expr, info *types.Info) bool {
|
||
|
|
se, ok := ex.(*ast.SelectorExpr)
|
||
|
|
if !ok || se.Sel.Name != "EOF" {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
if ep, ok := asImportedName(se.X, info); !ok || ep != "io" {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
func asImportedName(ex ast.Expr, info *types.Info) (string, bool) {
|
||
|
|
ei, ok := ex.(*ast.Ident)
|
||
|
|
if !ok {
|
||
|
|
return "", false
|
||
|
|
}
|
||
|
|
|
||
|
|
ep, ok := info.ObjectOf(ei).(*types.PkgName)
|
||
|
|
if !ok {
|
||
|
|
return "", false
|
||
|
|
}
|
||
|
|
|
||
|
|
return ep.Imported().Path(), true
|
||
|
|
}
|
||
|
|
|
||
|
|
func areBothErrors(x, y ast.Expr, typesInfo *types.Info) bool {
|
||
|
|
// check that both left and right hand side are not nil
|
||
|
|
if typesInfo.Types[x].IsNil() || typesInfo.Types[y].IsNil() {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
// check that both left and right hand side are not io.EOF
|
||
|
|
if isEOF(x, typesInfo) || isEOF(y, typesInfo) {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
// check that both left and right hand side are errors
|
||
|
|
if !isError(x, typesInfo) && !isError(y, typesInfo) {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
func rawString(x ast.Expr) string {
|
||
|
|
switch t := x.(type) {
|
||
|
|
case *ast.Ident:
|
||
|
|
return t.Name
|
||
|
|
case *ast.SelectorExpr:
|
||
|
|
return fmt.Sprintf("%s.%s", rawString(t.X), t.Sel.Name)
|
||
|
|
case *ast.CallExpr:
|
||
|
|
return fmt.Sprintf("%s()", rawString(t.Fun))
|
||
|
|
}
|
||
|
|
return fmt.Sprintf("%s", x)
|
||
|
|
}
|